How to model this irregular shape
I am not an Expert about blender, but i can help you.

Start off with a cube.

Go in edit mode.

Subdivide the cube by a small value (4).

Grab the edge you want to pull inwards ONLY ON ONE SIDE!

Move the selected edge inwards. (G Key).

Exit edit mode.

Apply a mirrors modifier (use the correct axis).

Now you should have the curve on both sides.

Grab the intact face on the back.

Extrude It where you want that  "long rectangle" to be.(E Key).

And grab the tip face of the long rectangle.

Inset that face a bit.(I Key)

Extrude the insetted face inwards.

Grab The Bottom of your creation.

Extrude It Down.(E Key).

Enable Shade Smooth.

P.S.
If the model looks weird After Shade Smooth, go ahead and enable Auto Smooth Normals!

I'm Sorry this Is a bit of a weird and probably not correct answer, but i've fine my best.
Hope you Will understand It.